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View Full Version : Skid again... it's static after all?


CreeDo
03-14-2010, 12:44 PM
I was watching TAR17 and Corey mentioned that they had run a test about the cause of skid (aka "kick" in the snooker world) and determined that it was static electricity.

A few guys on these forums also mentioned the idea but at the time I was skeptical.

One post I read on here says that a physicist in a BBC documentary tested the theory to see if it's either dirty balls OR static. His result was apparently that it was neither, but the poster didn't remember how they disproved static. He did remember that they cleaned the hell out of the balls with ethanol and shot with an unchalked tip to disprove dirt... even with these conditions the ball eventually kicked.

The latest theory was it has something to do with the oils used to create the balls. I guess some property of the (petroleum-based?) plastic resin maybe causes it to get funny patches. Or it 'sweats'? I didn't quite follow.

So was corey talking about the same BBC documentary I wonder? Or something more recent? Either he or the poster were misremembering the conclusions.

Static might explain why some people swear it happens on some types of cloth more than others.

DRW
03-14-2010, 01:17 PM
I was watching TAR17 and Corey mentioned that they had run a test about the cause of skid (aka "kick" in the snooker world) and determined that it was static electricity.

A few guys on these forums also mentioned the idea but at the time I was skeptical.

One post I read on here says that a physicist in a BBC documentary tested the theory to see if it's either dirty balls OR static. His result was apparently that it was neither, but the poster didn't remember how they disproved static. He did remember that they cleaned the hell out of the balls with ethanol and shot with an unchalked tip to disprove dirt... even with these conditions the ball eventually kicked.

The latest theory was it has something to do with the oils used to create the balls. I guess some property of the (petroleum-based?) plastic resin maybe causes it to get funny patches. Or it 'sweats'? I didn't quite follow.

So was corey talking about the same BBC documentary I wonder? Or something more recent? Either he or the poster were misremembering the conclusions.

Static might explain why some people swear it happens on some types of cloth more than others.

It definitely appears to happen with new cloth more often. I used to take a break from pool when the room I was a regular in would change the cloth. I still hate it. It changes everything about the tables. Bank angles, pocket acceptance. You would think with all the technological advances in everything else, that cloth manufacturers would be able to make a new cloth with already broke in qualities. The skid also appears to happen at a certain speed of contact. Never seen one skid when it was hit like a rocket.

measureman
03-14-2010, 01:20 PM
Just an observation of 50+ years of playing. I have noticed that the softer you hit the shot and the thinner the cut is where most of skids occur. My thinking is that the ball does not start to roll but slides a little first therefor creating the skid effect. So different balls and different cloth may intensify the slide. So to me it is as simple as severe cut and slow cue ball speed. Every time i am forced to thin cut a ball with a feather stroke i wonder if it will skid.

9bizzle
03-14-2010, 02:05 PM
In my experience it's not just a slide, but almost a double kiss phenomenon happening between cb and ob. You can hear it when it happens. Or maybe it's that one of the balls has left the table slightly and that's what I'm hearing. I'd like to see Dr. Dave catch this and analyze it in slo-mo.

3kushn
03-14-2010, 02:10 PM
I don't have any scientific proof but it stands to reason at least for me that a new bed and rail cloth has no chalk all over it and therefore no added friction from the gritty abrasive chalk. Thus its simply more slippery. Add new balls with no scratches which add to the friction and its double slip and slide.

The above comments I suppose explains why pool halls don't need to keep things as clean as with carom games where we need slide for the balls to act properly off a rail. With a non sliding table many shots are simply impossible to make.:angry: The table robs all the spin and shortens the angles. Its much easier to shorten a shot on a long table than lengthen a shot on a short table. This is a battle that will never be won in most pool halls I suppose. :deadhorse::banghead:

I think I'll just have go spray some silicone on my month old cloth. Its starting to shorten up.:poke:

CreeDo
03-14-2010, 08:48 PM
You definitely hear a skid, and it does almost sound like a super fast double hit. It's sort of a clack or clud. It's a lot like the sound when you do a fast double hit with the tip, aka a push foul.

That's sharp thinking 9beezy. Maybe one ball is leaving the table and climbing up the other ball for a split second before dropping back to the slate. It also kinda backs up what I and some other people notice... you don't get a skid with a fast sliding cut. It seems to happen when you have a rolling cue ball. And I don't know that I've ever gotten it with backspin on the CB. So... the increased contact is causing the CB to climb up the face of the OB a hair and then immediately drop, creating that double hit sound.

I wish I could comment on different cloths but I haven't noticed the difference in one cloth vs. another. I don't play on a lot of different ones.

I gotta be honest measureman, I've never seen it on a thin cut. I think when a thin cut seems to undercut, it's the regular bit of throw that you get on any cut. It's just that a thin cut has such a small margin for error, that throwing it a hair always makes it look like it missed by a foot. My feeling is that skid seems worst when normal throw seems worst... medium angles between... I dunno... 20 and 50 degrees. I'll try rolling a few thin cuts. Maybe I don't see it cuz I hit thin ones pretty firmly.

Something I know for sure is true... dirtiness and chalk do make a ball throw like crazy. If you rub some chalk directly on a ball and then do a soft shot with heavy throw, it'll get knocked sideways like crazy. So I always felt sure skid was caused by this. But now after hearing the ethanol-cleaned-balls story, I'm not so sure.

vasilios
03-14-2010, 09:25 PM
when a cue ball in motion contacts an object ball wich is in a static position a transfer of energy must take place.(time of transfer will vary on conditions).after transfer the object ball will travel until the energy is depleted.the cue will use its remaining energy until it is depleted.the target paths for both balls are converted at the same moment.dirty balls cling together longer during transfer than clean balls.you have to transfer the energy to the dirt first.same crap goes for the cloth,new old - dirty clean.thats what makes pool fun.never ending changing conditions.

bill

mullyman
03-14-2010, 10:26 PM
This is something I read somewhere a long time ago.....let me see if I can say it correctly.

When you hit the cue ball with your tip it leaves a bit of chalk on the ball. If that bit of chalk is in the right place at the right time, meaning the contact point between the balls, the CB will stick to the ball for a split second...just enough to cause the OB to skid.

Like I said, I read that somewhere. Sounded possible so I've just written it off as that for years.
MULLY

DogsPlayingPool
03-14-2010, 10:36 PM
when a cue ball in motion contacts an object ball wich is in a static position a transfer of energy must take place.(time of transfer will vary on conditions).after transfer the object ball will travel until the energy is depleted.the cue will use its remaining energy until it is depleted.the target paths for both balls are converted at the same moment.dirty balls cling together longer during transfer than clean balls.you have to transfer the energy to the dirt first.same crap goes for the cloth,new old - dirty clean.thats what makes pool fun.never ending changing conditions.

bill

I am in no position to dispute your analysis of the physics but I do disagree on one point: When you catch a skidder it is NOT fun! ;)

CreeDo, perhaps there are multiple causes. But I've got to think that chalk or other gritty dirt is at least one of them. It just makes sense to me intuitively. I can buy in to a big chalk mark on the CB "grabbing" the OB and taking it along for a bit before it releases it. Also (and I don't know the answer to this), can the amount of static electricity created, which I have to believe is fairly small, cause that big a reaction to 2 relatively heavy balls that have momentum?

Does anyone know if static electricity creates a noticeable spark? I've never seen one.

One other thing that may have relevance: I've been playing a long time and way back when I don't seem to recall encountering skidders as much as I do these days. Maybe it's just my fading memory or perhaps changes in cloth, ball material etc. have something to do with it.

pt109
03-14-2010, 10:43 PM
There can be several reasons for a skid.I believe static is
one of them.Years ago Jimmy White was getting a lot of
skids in a snooker match.The ref was wearing white nylon
gloves.The head ref gave him his cotton gloves and the
skids stopped.

mullyman
03-14-2010, 10:49 PM
Wiping very well will help stop skidding.
MULLY

Bob Jewett
03-14-2010, 11:46 PM
... He did remember that they cleaned the hell out of the balls with ethanol and shot with an unchalked tip to disprove dirt... even with these conditions the ball eventually kicked. ... Static might explain why some people swear it happens on some types of cloth more than others.
The reports I've heard of that test have been really sketchy. I think the cleaning agent was acetone. I think it's really a bad idea to "clean" plastic with something that would probably cause the manufacturer to cry out in pain.

It is easy to demonstrate skids using a little chalk on the balls. It was evidently hard to demonstrate it under the very unnatural conditions of UK test.

I think that actual static charge on the balls is very unlikely to produce enough force -- and certainly no direct sideways force -- to cause skid/kick/cling/bad-contact. If someone does think that static electricity on the balls can cause very large excess friction between the balls, he should present an analysis of how that can happen based on something other than Phlogiston (http://en.wikipedia.org/wiki/Phlogiston_theory).

A possible explanation that does include static electricity is that under some conditions, partly involving static electricity, chalk is more likely to stick to the cue ball than under other conditions. To see how much chalk is flying around during a shot, see the amazing
Efler/Leitner video (http://video.google.com/videoplay?docid=1708353497587857701#) -- about 37 seconds in.

CreeDo
03-15-2010, 12:00 AM
I follow you, as far as the chalk mark rotating into exactly the wrong place at the wrong time to cause a skid. And in an old post I said the exact same thing... "I can't believe the tiny bit of whatever caused by static electricity could possibly move something as big as a pool ball".

But now we have some fairly sharp players saying stuff that supports the static theory and I have my doubts. Even that bit about earl saying it happens more in cold weather... static electricity gets much worse in the winter. Cold dry air specifically makes it easier to build up a charge.

When the charge actually discharges, it does make a visible spark. Rub a balloon on the carpet and touch something metal (or maybe a nearby pet) in the dark. You'll see it easily. If this is a static thing, maybe we'll be able to see a tiny spark at the moment of impact? But then how would we witness the skid? >_<

We need to drag the science guys in here to settle this. That or maybe someone from the UK can hunt down that BBC clip.

Bob Jewett
03-15-2010, 12:46 AM
... But now we have some fairly sharp players saying stuff that supports the static theory ...
No, I think they only said that such a study existed. I don't think any player has examined the accuracy of the study.

DogsPlayingPool
03-15-2010, 07:32 AM
Note to self:

If, a year from now, I should want to find this thread again, do a search under "Phlogiston". :thumbup:

9bizzle
03-15-2010, 10:51 AM
Creedo, what you added to my observation makes a ton of sense. When you put it with the sound it adds up. Way to expound, Bro!!! 9beezy:grin:

bogey54311
03-15-2010, 11:33 AM
Wiping very well will help stop skidding.
MULLY

rep.



chris G

dr_dave
03-15-2010, 05:44 PM
I think the claim that static is a cause for cling/skid/kick is a bunch of hooey. I haven't tried to test the effects of static electricity because I know how small the forces involved with static electricity are. They are too miniscule to affect the dynamics of pool balls.

FYI, I have some resources on cling here:

http://billiards.colostate.edu/threads/throw.html#cling

Cling/skid/kick is just excessive throw, usually caused by a chalk smudge at the contact point.

Regards,
Dave

I was watching TAR17 and Corey mentioned that they had run a test about the cause of skid (aka "kick" in the snooker world) and determined that it was static electricity.

A few guys on these forums also mentioned the idea but at the time I was skeptical.

One post I read on here says that a physicist in a BBC documentary tested the theory to see if it's either dirty balls OR static. His result was apparently that it was neither, but the poster didn't remember how they disproved static. He did remember that they cleaned the hell out of the balls with ethanol and shot with an unchalked tip to disprove dirt... even with these conditions the ball eventually kicked.

The latest theory was it has something to do with the oils used to create the balls. I guess some property of the (petroleum-based?) plastic resin maybe causes it to get funny patches. Or it 'sweats'? I didn't quite follow.

So was corey talking about the same BBC documentary I wonder? Or something more recent? Either he or the poster were misremembering the conclusions.

Static might explain why some people swear it happens on some types of cloth more than others.

dr_dave
03-15-2010, 05:50 PM
You definitely hear a skid, and it does almost sound like a super fast double hit. It's sort of a clack or clud. It's a lot like the sound when you do a fast double hit with the tip, aka a push foul.For rolling CB shots, the sound is ball hop. See:

HSV B.46 - CB and OB hop and spin transfer during follow shots (http://billiards.colostate.edu/high_speed_videos/new/HSVB-46.htm)


Regards,
Dave

smoooothstroke
03-15-2010, 05:57 PM
It is the pool Gods exacting justice.

measureman
03-15-2010, 06:10 PM
Well I've read all the posts and i am still am not sure what causes a skid. But as one poster mentioned i don't remember balls skidding years ago when we played on the heavy nap cloth. But that was a long time ago.
I know when i first started to play and the balls were square we did have a lot of "slides" but after Moog (3 caves west) figured out how to make them round the slides stopped and we had "skids". :D

Tennesseejoe
03-15-2010, 06:20 PM
Has anyone ever experienced skid by using some low outside English? To explain further---just a little English on a slight cut and a lot on an extreme cut.

measureman
03-15-2010, 06:32 PM
Has anyone ever experienced skid by using some low outside English? To explain further---just a little English on a slight cut and a lot on an extreme cut.

If i just have to make a cut shot i always spin it in and can"t remember getting a skid. But if i have to thin cut it with a soft stroke center ball sometimes it will skid. I still think the object ball slides a little before rolling on a soft cut shot. Try thin cutting balls with a soft almost feather like stroke center cue ball and see what happens.

highrun55
03-15-2010, 07:01 PM
We have called that Simonis skid around my room since Simonis was first Installed on our tables


highrun55

measureman
03-15-2010, 07:18 PM
We have called that Simonis skid around my room since Simonis was first Installed on our tables


highrun55

You very well could be right. Slick cloth vs heavy nap cloth.

9bizzle
03-15-2010, 07:48 PM
For rolling CB shots, the sound is ball hop. See:

HSV B.46 - CB and OB hop and spin transfer during follow shots (http://billiards.colostate.edu/high_speed_videos/new/HSVB-46.htm)


Regards,
Dave

Thanks Dr.Dave!!!

CreeDo
03-15-2010, 11:52 PM
Clearly I gotta spend more time on dave's site. The familiar sound combined with the obvious visual hop (obvious at 1000 FPS) has convinced me he's showing us the true cause of skid, or at least the leading cause.

My initial instinct was that static couldn't possibly affect it too, I shoulda trusted that. I guess I let my mind get clouded by all the times a massive winter shock sent my hand flying away from a metal surface. But that's strictly nerves and muscles causing the reaction, not physics :P

donny mills
03-16-2010, 01:17 AM
When I played Mika in the semis at the us open I had this shot that I had to shoot a certain way and I knew it was gonna skid... and sure enough it skidded! Probably cost me the match.

memikey
03-16-2010, 03:19 AM
I've always believed ball on ball kicks was caused by chalk but have also always believed that static has an effect on how the chalk behaves.

Re static and how much physical effect it can have I know that if I comb my hair with a nylon comb for about 6 swift strokes I can easily divert the downward stream of water from a tap in a horizontal direction just by holding the static loaded comb next to the vertical stream. Static diverting a heavy pool/snooker ball at ball on ball contact is another matter right enough :smile:

Re another possible contributory cause sof skid, let's call it "cloth induced". I'm not sure if it has an effect on ball on ball skid normally but all those who played on brand new fitted Gorina cloth in IPT qualifiers or tourneys and ever played a bank or kick would certainly know how much the ball skidded on cushion contact....static? I don't know but it was huge :(

mikepage
03-16-2010, 03:23 PM
[...] If someone does think that static electricity on the balls can cause very large excess friction between the balls, he should present an analysis of how that can happen based on something other than Phlogiston (http://en.wikipedia.org/wiki/Phlogiston_theory).
[...]

Well if it doesn't come from a chemical reaction between the phlogiston and the ether, then I think there just might be a game of telephone going on here...

*****

Ralph to Mary: "It's caused by static friction."

Mary to Bill: "Ralph says it's caused by static."

Bill to Henry: "Yeah, let me explain: that's -ah- STATIC ELECTRICITY that causes that phenomenon"

Henry to Penelope: "Yeah, Bob Jewett proved with a high-speed camera it is caused by Static Electricity"

Penelope to Wilbur: "It's well known that Dr. Dave proved it is caused by Static Electricity in the Jacksonville Project."

ssminn
03-16-2010, 04:29 PM
My guess would be that static electricity it self does't cause the skid but the static electricity will cause chalk and other foreign material to stick to the cue ball and object ball, it is this chalk and other foreign material that will cause the balls to "gear" more and cause the skid.
I think I will apply for a government grant to test this theory, I'll give a new report when finished.

dr_dave
03-16-2010, 05:02 PM
Good one! :thumbup:

Well if it doesn't come from a chemical reaction between the phlogiston and the ether, then I think there just might be a game of telephone going on here...

*****

Ralph to Mary: "It's caused by static friction."

Mary to Bill: "Ralph says it's caused by static."

Bill to Henry: "Yeah, let me explain: that's -ah- STATIC ELECTRICITY that causes that phenomenon"

Henry to Penelope: "Yeah, Bob Jewett proved with a high-speed camera it is caused by Static Electricity"

Penelope to Wilbur: "It's well known that Dr. Dave proved it is caused by Static Electricity in the Jacksonville Project."

woody_968
03-16-2010, 05:35 PM
I have been one of the ones that has questioned if static could be one of the causes of a skid. I used to play in a room that kept their equipment very clean. Tables were cleaned at least daily, often more. Balls were cleaned daily, and many times they did it after every use. They used a ball machine, but didnt use cleaner or polish. I questioned if the friction between the fabric in the machine could possibly increase static enough to produce a skid.

I had never played in a room before that was kept so clean but the balls skidded more often. That was the reason I questioned static. But I sure dont claim to be smart enough to know how much static it would take to increase the friction enough to make a ball skid on a clean cloth :)

highrun55
03-16-2010, 05:55 PM
I believe that if there is a hand powder spot on both balls that touch, it will slide or skip to.
jmo

highrun55

CreeDo
03-16-2010, 10:56 PM
When I played Mika in the semis at the us open I had this shot that I had to shoot a certain way and I knew it was gonna skid... and sure enough it skidded! Probably cost me the match.

I dunno if you'll remember it but there was a pretty brutal skid you had late in the match with shane. Stuck on the rail with moderate angle on a corner shot. It undercut by like 1/3rd diamond. Then shane undercut two shots later and I think you also did one more.

Corey was calling all of them skids, I was curious if you feel the same way or if any of them just got undercut. And if they were all skids, what was going on with the cloth around that time, did it seem extra chalky or whatever?

pt109
03-16-2010, 11:48 PM
A woman gave me a lot of static once......
I ended up on skid row.....umm...might not be pertinent....